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Zhong Y, Zhang X, Yang Q, Wang Q. Hepatorenal Toxicity after 7-Day Oral Administration of Low-Dose Tetrodotoxin and Its Distribution in the Main Tissues in Mice. Toxins (Basel) 2023; 15:564. [PMID: 37755990 PMCID: PMC10538156 DOI: 10.3390/toxins15090564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/31/2023] [Accepted: 09/07/2023] [Indexed: 09/28/2023] Open
Abstract
Tetrodotoxin (TTX) is a highly toxic compound detected in various edible marine animals even in European waters. To characterize the hazard by oral exposure to TTX, its tissue distribution was evaluated after single (75 μg/kg) or 7-day (25-125 μg/kg) oral administration in mice. Moreover, TTX liver and renal toxicity was evaluated after 7-day oral administration. The elimination cycle of a single oral dose of TTX (75 µg/kg) was found to be approximately 168 h (7 days). Daily oral administration of TTX at doses of 25, 75, and 125 µg/kg for 7 consecutive days revealed dose-dependent toxic effects on the liver and kidney. Histopathological examination showed increased inflammatory cell infiltration in the liver and kidney with higher TTX doses, along with disorganization of the hepatic cord and renal tubular cell arrangement. The study results indicated that TTX had more hepatotoxicity than nephrotoxicity in mice. These findings provide insights into the unintentional ingestion of a low dose of TTX in mammals, including humans, and emphasize the importance of food safety.
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Affiliation(s)
- Yaqian Zhong
- School of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China; (Y.Z.); (Q.Y.); (Q.W.)
- Laboratory of Aquatic Product Processing and Quality Safety, Zhejiang Marine Fisheries Research Institute, Zhoushan 316100, China
| | - Xiaojun Zhang
- Laboratory of Aquatic Product Processing and Quality Safety, Zhejiang Marine Fisheries Research Institute, Zhoushan 316100, China
| | - Qiyu Yang
- School of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China; (Y.Z.); (Q.Y.); (Q.W.)
- Laboratory of Aquatic Product Processing and Quality Safety, Zhejiang Marine Fisheries Research Institute, Zhoushan 316100, China
| | - Qianfeng Wang
- School of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China; (Y.Z.); (Q.Y.); (Q.W.)
- Laboratory of Aquatic Product Processing and Quality Safety, Zhejiang Marine Fisheries Research Institute, Zhoushan 316100, China
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Wang Y, Zheng R, Wu P, Wu Y, Huang L, Huang L. Determination of Multiple Neurotransmitters through LC-MS/MS to Confirm the Therapeutic Effects of Althaea rosea Flower on TTX-Intoxicated Rats. Molecules 2023; 28:molecules28104158. [PMID: 37241898 DOI: 10.3390/molecules28104158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/10/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023] Open
Abstract
Tetrodotoxin (TTX) inhibits neurotransmission in animals, and there is no specific antidote. In clinical practice in China, Althaea rosea (A. rosea flower) extract has been used to treat TTX poisoning. In this work, the efficacy of the ethyl acetate fraction extract of A. rosea flower in treating TTX poisoning in rats was investigated. A high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to determine nine neurotransmitters in rat brain tissue, including γ-aminobutyric acid (GABA), dopamine (DA), 5-hydroxytryptamine (5-HT), noradrenaline (NE), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 5-hydroxyindole-3-acetic acid (5-HIAA), epinephrine (E), and tyramine (Tyn). The detoxifying effect of A. rosea flower was verified by comparing the changes in neurotransmitters' content in brain tissue before and after poisoning in rats. The assay was performed in multiple reaction monitoring mode. The quantification method was performed by plotting an internal-standard working curve with good linearity (R2 > 0.9941) and sensitivity. Analyte recoveries were 94.04-107.53% (RSD < 4.21%). Results indicated that the levels of 5-HT, DA, E, and NE in the brains of TTX-intoxicated rats decreased, whereas the levels of GABA, Tyn, and 5-HIAA showed an opposite trend, and HVA and DOPAC were not detected. The levels of all seven neurotransmitters returned to normal after the gavage administration of ethyl acetate extract of A. rosea flower to prove that the ethyl acetate extract of A. rosea flower had a therapeutic effect on TTX poisoning. The work provided new ideas for studies on TTX detoxification.
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Affiliation(s)
- Yichen Wang
- School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
| | - Renjin Zheng
- School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
- Fujian Provincial Center for Disease Control and Prevention, Physical and Chemical Analysis Department, Fuzhou 350001, China
| | - Pingping Wu
- School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
| | - Youjia Wu
- School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
| | - Lingyi Huang
- School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
| | - Liying Huang
- School of Pharmacy, Fujian Medical University, Fuzhou 350122, China
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Wang F, Zhang F, Song J, Zou S, Li J, Huang Y, Zhang L, Wang Q. Acute Toxic Effects of Tetrodotoxin in Mice via Intramuscular Injection and Oral Gavage. Toxins (Basel) 2023; 15:toxins15050334. [PMID: 37235368 DOI: 10.3390/toxins15050334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/11/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
Tetrodotoxin (TTX) is a highly fatal marine biotoxin. Constantly increasing intoxications and the lack of specific antitoxic drugs in clinical applications highlight the need for further research into the toxic effects of TTX. Current reports on poisoning cases and the TTX toxicity mechanism suggest that the blocking of voltage-gated sodium channels (VGSCs) by TTX is probably reversible, but direct evidence of this is lacking, as far as we are aware. This study explored the acute toxic effects of TTX at sub-lethal doses via different routes, analyzing variations in muscle strength and TTX concentration in the blood in mice. We found that the loss of muscle strength in mice caused by TTX was dose-dependent and reversible, and the death time and muscle strength variations after oral gavage with TTX appeared to occur later and were more variable than those after intramuscular injection. In conclusion, we systematically compared the acute toxic effects of TTX for two different administration routes at sub-lethal doses, directly verifying the reversible reaction of TTX blocking VGSCs and speculating that averting a complete block of VGSCs by TTX could be an effective strategy for preventing death from TTX poisoning. This work may provide data for the diagnosis and treatment of TTX poisoning.
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Affiliation(s)
- Fan Wang
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Center, Naval Medical University, Shanghai 200433, China
| | - Fuhai Zhang
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Center, Naval Medical University, Shanghai 200433, China
| | - Juxingsi Song
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Center, Naval Medical University, Shanghai 200433, China
| | - Shuaijun Zou
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Center, Naval Medical University, Shanghai 200433, China
| | - Jie Li
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Center, Naval Medical University, Shanghai 200433, China
| | - Yichao Huang
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Center, Naval Medical University, Shanghai 200433, China
| | - Liming Zhang
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Center, Naval Medical University, Shanghai 200433, China
| | - Qianqian Wang
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Center, Naval Medical University, Shanghai 200433, China
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Finch SC, Boundy MJ, Webb NG, Harwood DT. The Effect of Experimental Protocol on the Toxicity of Saxitoxin in Mice. Toxins (Basel) 2023; 15:290. [PMID: 37104228 PMCID: PMC10146210 DOI: 10.3390/toxins15040290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 04/04/2023] [Accepted: 04/14/2023] [Indexed: 04/28/2023] Open
Abstract
Regulatory limits for toxins in shellfish are required to ensure the health of consumers. However, these limits also impact the profitability of shellfish industries making it critical that they are fit for purpose. Since human toxicity data is rarely available, the setting of regulatory limits is dependent on animal data which can then be extrapolated for use in the assessment of human risk. The dependence on animal data to keep humans safe means that it is critical that the toxicity data used is robust and of high quality. Worldwide, the protocols used in toxicity testing are varied, making it hard to compare results and adding confusion over which results better reflect the true toxicity. In this study, we look at the effect of mouse gender, i.p. dose volume, mouse body weight and feeding protocols (both acute and sub-acute) on the toxicity of saxitoxin. This allowed the effect of different variables used in toxicity testing to be understood and showed that the feeding protocol used in both acute and sub-acute studies greatly influenced the toxicity of saxitoxin in mice. Therefore, the adoption of a standard protocol for the testing of shellfish toxins is recommended.
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Affiliation(s)
- Sarah C. Finch
- AgResearch Ltd. Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand;
| | - Michael J. Boundy
- Cawthron Institute, Private Bag 2, Nelson 7042, New Zealand; (M.J.B.); (D.T.H.)
| | - Nicola G. Webb
- AgResearch Ltd. Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand;
| | - D. Tim Harwood
- Cawthron Institute, Private Bag 2, Nelson 7042, New Zealand; (M.J.B.); (D.T.H.)
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In vivo subchronic effects of ciguatoxin-related compounds, reevaluation of their toxicity. Arch Toxicol 2022; 96:2621-2638. [PMID: 35657391 PMCID: PMC9325831 DOI: 10.1007/s00204-022-03315-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/11/2022] [Indexed: 11/22/2022]
Abstract
Ciguatoxins are marine compounds that share a ladder-shaped polyether structure produced by dinoflagellates of the genus Gambierdiscus and Fukuyoa, and include maitotoxins (MTX1 and MTX3), ciguatoxins (CTX3C) and analogues (gambierone), components of one of the most frequent human foodborne illness diseases known as ciguatera fish poisoning. This disease was previously found primarily in tropical and subtropical areas but nowadays, the dinoflagellates producers of ciguatoxins had spread to European coasts. One decade ago, the European Food Safety Authority has raised the need to complete the toxicological available data for the ciguatoxin group of compounds. Thus, in this work, the in vivo effects of ciguatoxin-related compounds have been investigated using internationally adopted guidelines for the testing of chemicals. Intraperitoneal acute toxicity was tested for maitotoxin 1 at doses between 200 and 3200 ng/kg and the acute oral toxicity of Pacific Ciguatoxin CTX3C at 330 and 1050 ng/kg and maitotoxin 1 at 800 ng/kg were also evaluated showing not effects on mice survival after a 96 h observation period. Therefore, for the following experiments the oral subchronic doses were between 172 and 1760 ng/kg for gambierone, 10 and 102 ng/kg for Pacific Ciguatoxin CTX3C, 550 and 1760 ng/kg for maitotoxin 3 and 800, 2560 and 5000 ng/kg for maitotoxin 1. The results presented here raise the need to reevaluate the in vivo activity of these agents. Although the intraperitoneal lethal dose of maitotoxin 1 is assumed to be 50 ng/kg, without chemical purity identifications and description of the bioassay procedures, in this work, an intraperitoneal lethal dose of 1107 ng/kg was obtained. Therefore, the data presented here highlight the need to use a common procedure and certified reference material to clearly establish the levels of these environmental contaminants in food.
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Louzao MC, Vilariño N, Vale C, Costas C, Cao A, Raposo-Garcia S, Vieytes MR, Botana LM. Current Trends and New Challenges in Marine Phycotoxins. Mar Drugs 2022; 20:md20030198. [PMID: 35323497 PMCID: PMC8950113 DOI: 10.3390/md20030198] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/04/2022] [Accepted: 03/05/2022] [Indexed: 02/04/2023] Open
Abstract
Marine phycotoxins are a multiplicity of bioactive compounds which are produced by microalgae and bioaccumulate in the marine food web. Phycotoxins affect the ecosystem, pose a threat to human health, and have important economic effects on aquaculture and tourism worldwide. However, human health and food safety have been the primary concerns when considering the impacts of phycotoxins. Phycotoxins toxicity information, often used to set regulatory limits for these toxins in shellfish, lacks traceability of toxicity values highlighting the need for predefined toxicological criteria. Toxicity data together with adequate detection methods for monitoring procedures are crucial to protect human health. However, despite technological advances, there are still methodological uncertainties and high demand for universal phycotoxin detectors. This review focuses on these topics, including uncertainties of climate change, providing an overview of the current information as well as future perspectives.
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Affiliation(s)
- Maria Carmen Louzao
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
- Correspondence: (M.C.L.); (L.M.B.)
| | - Natalia Vilariño
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Carmen Vale
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Celia Costas
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Alejandro Cao
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Sandra Raposo-Garcia
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
| | - Mercedes R. Vieytes
- Departamento de Fisiologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain;
| | - Luis M. Botana
- Departamento de Farmacologia, Facultad de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain; (N.V.); (C.V.); (C.C.); (A.C.); (S.R.-G.)
- Correspondence: (M.C.L.); (L.M.B.)
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Otero P, Silva M. Emerging Marine Biotoxins in European Waters: Potential Risks and Analytical Challenges. Mar Drugs 2022; 20:199. [PMID: 35323498 PMCID: PMC8955394 DOI: 10.3390/md20030199] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 02/15/2022] [Accepted: 03/05/2022] [Indexed: 01/21/2023] Open
Abstract
Harmful algal blooms pose a challenge regarding food safety due to their erratic nature and forming circumstances which are yet to be disclosed. The best strategy to protect human consumers is through legislation and monitoring strategies. Global warming and anthropological intervention aided the migration and establishment of emerging toxin producers into Europe's temperate waters, creating a new threat to human public health. The lack of information, standards, and reference materials delay effective solutions, being a matter of urgent resolution. In this work, the recent findings of the presence of emerging azaspiracids, spirolildes, pinnatoxins, gymnodimines, palitoxins, ciguatoxins, brevetoxins, and tetrodotoxins on European Coasts are addressed. The information concerning emerging toxins such as new matrices, locations, and toxicity assays is paramount to set the risk assessment guidelines, regulatory levels, and analytical methodology that would protect the consumers.
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Affiliation(s)
- Paz Otero
- Department of Pharmacology, Pharmacy and Pharmaceutical Technology, Faculty of Veterinary Science, Universidade de Santiago de Compostela, 27002 Lugo, Spain
| | - Marisa Silva
- MARE—Marine and Environmental Sciences Centre, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisbon, Portugal
- Department of Plant Biology, Faculty of Sciences, University of Lisbon, Campo Grande, 1749-016 Lisbon, Portugal
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Katikou P, Gokbulut C, Kosker AR, Campàs M, Ozogul F. An Updated Review of Tetrodotoxin and Its Peculiarities. Mar Drugs 2022; 20:md20010047. [PMID: 35049902 PMCID: PMC8780202 DOI: 10.3390/md20010047] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/28/2021] [Accepted: 12/30/2021] [Indexed: 12/19/2022] Open
Abstract
Tetrodotoxin (TTX) is a crystalline, weakly basic, colorless organic substance and is one of the most potent marine toxins known. Although TTX was first isolated from pufferfish, it has been found in numerous other marine organisms and a few terrestrial species. Moreover, tetrodotoxication is still an important health problem today, as TTX has no known antidote. TTX poisonings were most commonly reported from Japan, Thailand, and China, but today the risk of TTX poisoning is spreading around the world. Recent studies have shown that TTX-containing fish are being found in other regions of the Pacific and in the Indian Ocean, as well as the Mediterranean Sea. This review aims to summarize pertinent information available to date on the structure, origin, distribution, mechanism of action of TTX and analytical methods used for the detection of TTX, as well as on TTX-containing organisms, symptoms of TTX poisoning, and incidence worldwide.
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Affiliation(s)
- Panagiota Katikou
- Ministry of Rural Development and Food, Directorate of Research, Innovation and Education, Hapsa & Karatasou 1, 54626 Thessaloniki, Greece
- Correspondence: (P.K.); (F.O.)
| | - Cengiz Gokbulut
- Department of Pharmacology, Faculty of Medicine, Balikesir University, Balikesir 10145, Turkey;
| | - Ali Rıza Kosker
- Department of Seafood Processing Technology, Faculty of Fisheries, Cukurova University, Adana 01330, Turkey;
| | - Mònica Campàs
- IRTA, Ctra Poble Nou km 5.5, 43540 Sant Carles de la Ràpita, Spain;
| | - Fatih Ozogul
- Department of Seafood Processing Technology, Faculty of Fisheries, Cukurova University, Adana 01330, Turkey;
- Correspondence: (P.K.); (F.O.)
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Finch SC, Webb NG, Boundy MJ, Harwood DT, Munday JS, Sprosen JM, Cave VM, Broadhurst RB, Nicolas J. Sub-Acute Feeding Study of Saxitoxin to Mice Confirms the Effectiveness of Current Regulatory Limits for Paralytic Shellfish Toxins. Toxins (Basel) 2021; 13:toxins13090627. [PMID: 34564631 PMCID: PMC8473220 DOI: 10.3390/toxins13090627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/03/2021] [Accepted: 09/05/2021] [Indexed: 11/17/2022] Open
Abstract
Regulatory limits for shellfish toxins are required to protect human health. Often these limits are set using only acute toxicity data, which is significant, as in some communities, shellfish makes up a large proportion of their daily diet and can be contaminated with paralytic shellfish toxins (PSTs) for several months. In the current study, feeding protocols were developed to mimic human feeding behaviour and diets containing three dose rates of saxitoxin dihydrochloride (STX.2HCl) were fed to mice for 21 days. This yielded STX.2HCl dose rates of up to 730 µg/kg bw/day with no effects on food consumption, growth, blood pressure, heart rate, motor coordination, grip strength, blood chemistry, haematology, organ weights or tissue histology. Using the 100-fold safety factor to extrapolate from animals to humans yields a dose rate of 7.3 µg/kg bw/day, which is well above the current acute reference dose (ARfD) of 0.5 µg STX.2HCl eq/kg bw proposed by the European Food Safety Authority. Furthermore, to reach the dose rate of 7.3 µg/kg bw, a 60 or 70 kg human would have to consume 540 or 630 g of shellfish contaminated with PSTs at the current regulatory limit (800 µg/kg shellfish flesh), respectively. The current regulatory limit for PSTs therefore seems appropriate.
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Affiliation(s)
- Sarah C. Finch
- AgResearch Ltd. Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand; (N.G.W.); (J.M.S.); (V.M.C.); (R.B.B.)
- Correspondence:
| | - Nicola G. Webb
- AgResearch Ltd. Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand; (N.G.W.); (J.M.S.); (V.M.C.); (R.B.B.)
| | - Michael J. Boundy
- Cawthron Institute, Private Bag 2, Nelson 7042, New Zealand; (M.J.B.); (D.T.H.)
| | - D. Tim Harwood
- Cawthron Institute, Private Bag 2, Nelson 7042, New Zealand; (M.J.B.); (D.T.H.)
| | - John S. Munday
- Department of Pathobiology, School of Veterinary Science, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand;
| | - Jan M. Sprosen
- AgResearch Ltd. Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand; (N.G.W.); (J.M.S.); (V.M.C.); (R.B.B.)
| | - Vanessa M. Cave
- AgResearch Ltd. Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand; (N.G.W.); (J.M.S.); (V.M.C.); (R.B.B.)
| | - Ric B. Broadhurst
- AgResearch Ltd. Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand; (N.G.W.); (J.M.S.); (V.M.C.); (R.B.B.)
| | - Jeane Nicolas
- Ministry for Primary Industries–Manatu Ahu Matua, P.O. Box 2526, Wellington 6021, New Zealand;
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Carroll AR, Copp BR, Davis RA, Keyzers RA, Prinsep MR. Marine natural products. Nat Prod Rep 2021; 38:362-413. [PMID: 33570537 DOI: 10.1039/d0np00089b] [Citation(s) in RCA: 198] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This review covers the literature published in 2019 for marine natural products (MNPs), with 719 citations (701 for the period January to December 2019) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1490 in 440 papers for 2019), together with the relevant biological activities, source organisms and country of origin. Pertinent reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. Methods used to study marine fungi and their chemical diversity have also been discussed.
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Affiliation(s)
- Anthony R Carroll
- School of Environment and Science, Griffith University, Gold Coast, Australia. and Griffith Institute for Drug Discovery, Griffith University, Brisbane, Australia
| | - Brent R Copp
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | - Rohan A Davis
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, Australia and School of Enivironment and Science, Griffith University, Brisbane, Australia
| | - Robert A Keyzers
- Centre for Biodiscovery, School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Michèle R Prinsep
- Chemistry, School of Science, University of Waikato, Hamilton, New Zealand
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Puddick J, van Ginkel R, Page CD, Murray JS, Greenhough HE, Bowater J, Selwood AI, Wood SA, Prinsep MR, Truman P, Munday R, Finch SC. Acute toxicity of dihydroanatoxin-a from Microcoleus autumnalis in comparison to anatoxin-a. CHEMOSPHERE 2021; 263:127937. [PMID: 32828056 DOI: 10.1016/j.chemosphere.2020.127937] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/03/2020] [Accepted: 08/05/2020] [Indexed: 06/11/2023]
Abstract
The cyanobacterium Microcoleus autumnalis grows as thick benthic mats in rivers and is becoming increasingly prevalent around the world. M. autumnalis can produce high concentrations of anatoxins and ingestion of benthic mats has led to multiple dog deaths over the past two decades. M. autumnalis produces a suite of different anatoxin congeners including anatoxin-a (ATX), dihydroanatoxin-a, (dhATX), homoanatoxin-a and dihydrohomoanatoxin-a. Benthic mat samples often contain high levels of dhATX, but there is little toxicology information on this congener. In the present study, natural versions of dhATX and ATX were purified from cyanobacteria to determine the acute toxicity by different routes of administration using mice. Nuclear magnetic resonance spectroscopy was used to confirm the putative structure of dhATX. By intraperitoneal (ip) injection, the median lethal dose (LD50) for dhATX was 0.73 mg/kg, indicating a reduced toxicity compared to ATX (LD50 of 0.23 mg/kg). However, by oral administration (both gavage and feeding), dhATX was more toxic than ATX (gavage LD50 of 2.5 mg/kg for dhATX and 10.6 mg/kg for ATX; feeding LD50 of 8 mg/kg for dhATX and 25 mg/kg for ATX). The relative nicotinic acetylcholine receptor-binding affinities of ATX and dhATX were determined using the Torpedo electroplaque assay which showed consistency with the relative toxicity determined by ip injection. This work highlights that toxicity studies based solely on ip injection may not yield LD50 values that are relevant to those derived via oral administration, and hence, do not provide a good estimate of the risk posed to human and animal health in situations where oral ingestion is the likely route of exposure. The high acute oral toxicity of dhATX, and its abundance in M. autumnalis proliferations, demonstrates that it is an important environmental contaminant that warrants further investigation.
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Affiliation(s)
| | - Roel van Ginkel
- Cawthron Institute, Private Bag 2, Nelson, 7042, New Zealand
| | - Carrie D Page
- Cawthron Institute, Private Bag 2, Nelson, 7042, New Zealand
| | - J Sam Murray
- Cawthron Institute, Private Bag 2, Nelson, 7042, New Zealand
| | | | - Joel Bowater
- Cawthron Institute, Private Bag 2, Nelson, 7042, New Zealand
| | | | - Susanna A Wood
- Cawthron Institute, Private Bag 2, Nelson, 7042, New Zealand
| | - Michèle R Prinsep
- Chemistry, School of Science, University of Waikato, Private Bag 3105, Hamilton, 3240, New Zealand
| | - Penelope Truman
- Massey University, PO Box 756, Wellington, 6140, New Zealand
| | - Rex Munday
- AgResearch Limited, Ruakura Research Centre, Private Bag 3123, Hamilton, 3240, New Zealand
| | - Sarah C Finch
- AgResearch Limited, Ruakura Research Centre, Private Bag 3123, Hamilton, 3240, New Zealand
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Boente-Juncal A, Raposo-García S, Vale C, Louzao MC, Otero P, Botana LM. In Vivo Evaluation of the Chronic Oral Toxicity of the Marine Toxin Palytoxin. Toxins (Basel) 2020; 12:toxins12080489. [PMID: 32751719 PMCID: PMC7472043 DOI: 10.3390/toxins12080489] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/24/2020] [Accepted: 07/28/2020] [Indexed: 01/22/2023] Open
Abstract
Palytoxin (PLTX) is one of the most poisonous substances known to date and considered as an emergent toxin in Europe. Palytoxin binds to the Na+-K+ ATPase, converting the enzyme in a permeant cation channel. This toxin is known for causing human fatal intoxications associated with the consumption of contaminated fish and crustaceans such as crabs, groupers, mackerel, and parrotfish. Human intoxications by PLTX after consumption of contaminated fishery products are a serious health issue and can be fatal. Different reports have previously explored the acute oral toxicity of PLTX in mice. Although the presence of palytoxin in marine products is currently not regulated in Europe, the European Food Safety Authority expressed its opinion on PLTX and demanded assessment for chronic toxicity studies of this potent marine toxin. In this study, the chronic toxicity of palytoxin was evaluated after oral administration to mice by gavage during a 28-day period. After chronic exposure of mice to the toxin, a lethal dose 50 (LD50) of 0.44 µg/kg of PLTX and a No-Observed-Adverse-Effect Level (NOAEL) of 0.03 µg/kg for repeated daily oral administration of PLTX were determined. These results indicate a much higher chronic toxicity of PLTX and a lower NOAEL than that previously described in shorter treatment periods, pointing out the need to further reevaluate the levels of this compound in marine products.
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Affiliation(s)
| | | | - Carmen Vale
- Correspondence: (C.V.); (L.M.B.); Tel./Fax: +34-982822233 (L.M.B.)
| | | | | | - Luis M. Botana
- Correspondence: (C.V.); (L.M.B.); Tel./Fax: +34-982822233 (L.M.B.)
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Boente-Juncal A, Otero P, Rodríguez I, Camiña M, Rodriguez-Vieytes M, Vale C, Botana LM. Oral Chronic Toxicity of the Safe Tetrodotoxin Dose Proposed by the European Food Safety Authority and Its Additive Effect with Saxitoxin. Toxins (Basel) 2020; 12:E312. [PMID: 32397553 PMCID: PMC7291010 DOI: 10.3390/toxins12050312] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 12/25/2022] Open
Abstract
Tetrodotoxin (TTX) is a potent natural toxin causative of human food intoxications that shares its mechanism of action with the paralytic shellfish toxin saxitoxin (STX). Both toxins act as potent blockers of voltage-gated sodium channels. Although human intoxications by TTX were initially described in Japan, nowadays increasing concern about the regulation of this toxin in Europe has emerged due to its detection in fish and mollusks captured in European waters. Currently, TTX is only regularly monitored in Dutch fishery products. However, the European Food Safety Authority (EFSA) has established a safety level of 44 µg/kg TTX as the amount of toxin that did not cause adverse effects in humans. This level was extrapolated considering initial data on its acute oral toxicity and EFSA remarked the need for chronic toxicity studies to further reduce the uncertainty of future toxin regulations. Thus, in this work, we evaluated the oral chronic toxicity of TTX using the safety levels initially recommended by EFSA in order to exclude potential human health risks associated with the worldwide expanding presence of TTX. Using internationally recommended guidelines for the assessment of oral chronic toxicity, the data provided here support the proposed safety level for TTX as low enough to prevent human adverse effects of TTX even after chronic daily exposure to the toxin. However, the combination of TTX with STX at doses above the maximal exposure level of 5.3 µg/kg body weight derived by EFSA increased the lethality of TTX, thus confirming that both TTX and paralytic shellfish toxins should be taken into account to assess human health risks.
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Affiliation(s)
- Andrea Boente-Juncal
- Laboratorio de Farmacología, Farmacia e Tecnoloxía Farmacéutica, Universidade de Santiago de Compostela, Facultad de Veterinaria, Campus Universitario s/n, 27002 Lugo, Spain; (A.B.-J.); (P.O.)
| | - Paz Otero
- Laboratorio de Farmacología, Farmacia e Tecnoloxía Farmacéutica, Universidade de Santiago de Compostela, Facultad de Veterinaria, Campus Universitario s/n, 27002 Lugo, Spain; (A.B.-J.); (P.O.)
| | - Inés Rodríguez
- Laboratorios Cifga, Benigno Rivera, 56, 27003 Lugo, Spain;
| | - Mercedes Camiña
- Departamento de Fisiología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain; (M.C.); (M.R.-V.)
| | - Mercedes Rodriguez-Vieytes
- Departamento de Fisiología, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain; (M.C.); (M.R.-V.)
| | - Carmen Vale
- Laboratorio de Farmacología, Farmacia e Tecnoloxía Farmacéutica, Universidade de Santiago de Compostela, Facultad de Veterinaria, Campus Universitario s/n, 27002 Lugo, Spain; (A.B.-J.); (P.O.)
| | - Luis M. Botana
- Laboratorio de Farmacología, Farmacia e Tecnoloxía Farmacéutica, Universidade de Santiago de Compostela, Facultad de Veterinaria, Campus Universitario s/n, 27002 Lugo, Spain; (A.B.-J.); (P.O.)
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Reevaluation of the acute toxicity of palytoxin in mice: Determination of lethal dose 50 (LD 50) and No-observed-adverse-effect level (NOAEL). Toxicon 2020; 177:16-24. [PMID: 32056831 DOI: 10.1016/j.toxicon.2020.01.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 01/17/2020] [Accepted: 01/22/2020] [Indexed: 12/27/2022]
Abstract
Palytoxin is an emergent toxin in Europe and one of the most toxic substances know to date. The toxin disrupts the physiological functioning of the Na+/K+-ATPase converting the enzyme in a permeant cation channel. Human intoxications by PLTX after consumption of contaminated fishery products are a serious health issue and can be fatal. Several reports have previously investigated the oral and intraperitoneal toxicity of PLTX in mice. However, in all cases short observation periods (24 and 48 h) after toxin administration were evaluated. In this work, single oral or intraperitoneal doses of PLTX were administered to healthy mice and surviving animals were followed up for 96 h. The data obtained here allowed us to calculate the oral and intraperitoneal lethal doses 50 (LD50) which were in the range of the values previously described. Surprisingly, the oral NOAEL for PLTX was more than 10 times lower than that previously described, a fact that indicates the need for the reevaluation of the levels of the toxin in edible fishery products.
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Biessy L, Boundy MJ, Smith KF, Harwood DT, Hawes I, Wood SA. Tetrodotoxin in marine bivalves and edible gastropods: A mini-review. CHEMOSPHERE 2019; 236:124404. [PMID: 31545201 DOI: 10.1016/j.chemosphere.2019.124404] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 07/13/2019] [Accepted: 07/18/2019] [Indexed: 06/10/2023]
Abstract
Tetrodotoxin (TTX) is a potent neurotoxin responsible for countless human intoxications and deaths around the world. The distribution of TTX and its analogues is diverse and the toxin has been detected in organisms from both marine and terrestrial environments. Increasing detections seafood species, such as bivalves and gastropods, has drawn attention to the toxin, reinvigorating scientific interest and regulatory concerns. There have been reports of TTX in 21 species of bivalves and edible gastropods from ten countries since the 1980's. While TTX is structurally dissimilar to saxitoxin (STX), another neurotoxin detected in seafood, it has similar sodium channel blocking action and potency and both neurotoxins have been shown to have additive toxicities. The global regulatory level for the STX group toxins applied to shellfish is 800 μg/kg. The presence of TTX in shellfish is only regulated in one country; The Netherlands, with a regulatory level of 44 μg/kg. Due to the recent interest surrounding TTX in bivalves, the European Food Safety Authority established a panel to assess the risk and regulation of TTX in bivalves, and their final opinion was that a concentration below 44 μg of TTX per kg of shellfish would not result in adverse human effects. In this article, we review current knowledge on worldwide TTX levels in edible gastropods and bivalves over the last four decades, the different methods of detection used, and the current regulatory status. We suggest research needs that will assist with knowledge gaps and ultimately allow development of robust monitoring and management protocols.
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Affiliation(s)
- Laura Biessy
- Cawthron Institute, Private Bag 2, Nelson, 7010, New Zealand; Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton, 3240, New Zealand; New Zealand Food Safety Science & Research Centre, Palmerston North, 4442, New Zealand.
| | | | - Kirsty F Smith
- Cawthron Institute, Private Bag 2, Nelson, 7010, New Zealand.
| | - D Tim Harwood
- Cawthron Institute, Private Bag 2, Nelson, 7010, New Zealand; New Zealand Food Safety Science & Research Centre, Palmerston North, 4442, New Zealand.
| | - Ian Hawes
- Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton, 3240, New Zealand.
| | - Susanna A Wood
- Cawthron Institute, Private Bag 2, Nelson, 7010, New Zealand.
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Katikou P. Public Health Risks Associated with Tetrodotoxin and Its Analogues in European Waters: Recent Advances after The EFSA Scientific Opinion. Toxins (Basel) 2019; 11:E240. [PMID: 31035492 PMCID: PMC6562576 DOI: 10.3390/toxins11050240] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 04/20/2019] [Accepted: 04/24/2019] [Indexed: 12/22/2022] Open
Abstract
Tetrodotoxin (TTX) and its analogues are naturally occurring toxins responsible worldwide for human intoxication cases and fatalities, mainly associated with pufferfish consumption. In the last decade, TTXs were detected in marine bivalves and gastropods from European waters. As TTXs are not regulated or monitored at EU level, their unexpected occurrence in shellfish raised concerns as a food safety hazard and revealed the necessity of a thorough assessment on the public health risks associated with their presence. For this reason, the European Food Safety Authority (EFSA) was requested by the European Commission to provide a scientific opinion, finally adopted in March 2017, according to which a provisional concentration below 44 μg TTX equivalents/kg shellfish meat, based on a large portion size of 400 g, was considered not to result in adverse effects in humans. The EFSA expert panel, however, recognized a number of shortcomings and uncertainties related to the unavailability of sufficient scientific data and provided relevant recommendations for future research to overcome these data gaps identified in order to further refine the risk assessment on TTXs. The present review aims to summarize the knowledge obtained towards addressing these recommendations in the two years following publication of the EFSA opinion, at the same time highlighting the points requiring further investigation.
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Affiliation(s)
- Panagiota Katikou
- Ministry of Rural Development and Food, Directorate General of Rural Development, Directorate of Research, Innovation and Education, Hapsa & Karatasou 1, 54626 Thessaloniki, Greece.
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